Polyurethane – nach 50 Jahren immer noch jung

Abstract

Polyurethane, die wohl vielseitigste Klasse von Hochpolymeren, sind aus der Technik und auch aus unserem Alltag nicht mehr wegzudenken. Vor über 50 Jahren erfunden, ist der Gipfel ihrer Entwicklung noch nicht in Sicht.

Isocyanate‐ and Phosgene‐Free Routes to Polyfunctional Cyclic Carbonates and Green Polyurethanes by Fixation of Carbon Dioxide

“…In 1947, Otto Bayer pioneered polyurethanes (PU) as a highly versatile class of polymeric materials, prepared by polyaddition of di‐ and polyisocyanates with short‐ and long‐chain polyols . Owing to the facile variation of isocyanate and polyol components in formulations, PUs are readily tailored for diversified applications ranging from flexible foams for bed mattresses and automotive seats to rigid foams for thermal insulation, scratch‐ and corrosion‐resistant coatings, elastomer fibers for textiles, and components of adhesives and sealants . Typically, special safety precautions are required for handling the highly toxic and water‐sensitive isocyanate monomers.…”

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isocyanate and polyol components in formulations, PUs are readily tailored for diversifi ed applications ranging from fl exible foams for bed mattresses and automotive seats to rigid foams for thermal insulation, scratch-and corrosionresistant coatings, elastomer fi bers for textiles, and components of adhesives and sealants. [ 2 ] Typically, special safety precautions are required for handling the highly toxic and water-sensitive isocyanate monomers. In the industrial isocyanate production, amines are converted into isocyanates by reacting them with phosgene, derived from chlorine and carbon monoxide.

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Evolution of Reaction‐Induced Phase Segregations in Bi‐Soft Segment Urethane Oligomers

“…[16] Successively, HDI was added in a molar ratio of NCO to OH groups of 3:2 and the reaction was allowed to proceed until the theoretical NCO content (NCO% theo ) is reached. 1 H-NMR was used to study the kinetics of the conversion of HDI with an equimolar polyol mixture comprising secondary and primary OH groups. For this, ITPU 0.54 (Table 1) was prepared as follows: 14.34 g (0.0242 mol) PEO 590 and 48.45 g (0.0242 mol) PPO 2000 was introduced into a round-bottom flask equipped with a magnetic stirrer.…”

“…The result was given in weight percentage of NCO groups with respect to sample weight (NCO%). The titrated NCO contents were used to determine the degree of conversion of NCO groups at time t (U t ) according to Equation (1).…”

“…Due to their versatile morphology, polyurethanes (PU) have entered practically all fields of polymer applications (e.g., foams, thermoplastic parts, adhesives, elastomers, or coatings). [1][2][3] This is particularly a result of the huge variability in raw materials that allows to tailor the properties of PU materials simply by appropriate choice of the educts. [4] PUs are typically obtained by reaction of aliphatic/aromatic polyisocyanates with different oligomeric or polymeric polyols (e.g., polyethers, polyesters, polycarbonates, polysiloxanes) and (optionally) low molecular weight polyols such as 1,4-butanediol or glycerol.…”